Tag Archives: Other Quantitative Biology

Direct In-Situ Capture, Separation and Visualization of Biological Particles with Fluid-Screen in the Context of Venus Life Finder Mission Concept Study [IMA]

Posted on by

http://arxiv.org/abs/2211.04572


Evidence of chemical disequilibria and other anomalous observations in the Venusian atmosphere motivate the search for life within the planet’s temperate clouds. To find signs of a Venusian aerial biosphere, a dedicated astrobiological space mission is required. Venus Life Finder (VLF) missions encompass unique mission concepts with specialized instruments to search for habitability indicators, biosignatures and even life itself. A key in the search for life is direct capture, concentration and visualization of particles of biological potential. Here, we present a short overview of Fluid-Screen (FS) technology, a recent advancement in the dielectrophoretic (DEP) microbial particle capture, concentration and separation. FS is capable of capturing and separating biochemically diverse particles, including multicellular molds, eukaryotic cells, different species of bacteria and even viruses, based on particle dielectric properties. In this short communication, we discuss the possible implementation of Fluid-Screen in the context of the VLF missions, emphasizing the unique science output of the Fluid-Screen instrument. FS can be coupled with other highly sophisticated instruments such as an autofluorescence microscope or a laser desorption mass spectrometer. We discuss possible configurations of Fluid-Screen that upon modification and testing, could be adapted for Venus. We discuss the unique science output of the FS technology that can capture biological particles in their native state and hold them in the focal plane of the microscope for the direct imaging of the captured material. We discuss the challenges for the proposed method posed by the concentrated sulfuric acid environment of Venus’ clouds. While Venus’ clouds are a particularly challenging environment, other bodies of the solar system, e.g., with liquid water present, might be especially suitable for Fluid-Screen application.

Read this paper on arXiv…

R. Weber, J. Petkowski and M. Weber
Thu, 10 Nov 22
37/78

Comments: Published in Aerospace as a part of the Special Issue “The Search for Signs of Life on Venus: Science Objectives and Mission Designs” (this https URL)

The Futility of Exoplanet Biosignatures [EPA]

Posted on by

http://arxiv.org/abs/2205.07921


The ultimate goal of astrobiology is to determine the distribution and diversity of life in the universe. But as the word “biosignature” suggests, what will be detected is not life itself, but an observation implicating a particular process associated with living systems. Technical constraints and our limited access to other worlds suggest we are more likely to detect an out-of-equilibrium suite of gasses than a writhing octopus. Yet, anything short of a writhing octopus will raise skepticism among astrobiologists about what has been detected. Resolving that skepticism requires a theory to delineate processes due to life and those due solely to abiotic mechanisms. This poses an existential question for the endeavor of life detection: How do astrobiologists plan to detect life via features shared between non-living and living systems? We argue that you cannot without an underlying theory of life. We illustrate this by analyzing the hypothetical detection of an “Earth 2.0” exoplanet. In the absence of a theory of life, we argue the community should focus on identifying unambiguous features of life via four areas of active research: understanding the principles of life on Earth, building life in the lab, detecting life in the solar system and searching for technosignatures. Ultimately, we ask, what exactly do astrobiologists hope to learn by searching for life?

Read this paper on arXiv…

H. Smith and C. Mathis
Wed, 18 May 22
55/66

Comments: 15 pages, 2 figures, 1 box

Biocosmology: Towards the birth of a new science [CEA]

Posted on by

http://arxiv.org/abs/2204.09378


Cosmologists wish to explain how our Universe, in all its complexity, could ever have come about. For that, we assess the number of states in our Universe now. This plays the role of entropy in thermodynamics of the Universe, and reveals the magnitude of the problem of initial conditions to be solved. The usual budgeting accounts for gravity, thermal motions, and finally the vacuum energy whose entropy, given by the Bekenstein bound, dominates the entropy budget today. There is however one number which we have not accounted for: the number of states in our complex biosphere. What is the entropy of life and is it sizeable enough to need to be accounted for at the Big Bang? Building on emerging ideas within theoretical biology, we show that the configuration space of living systems, unlike that of their fundamental physics counterparts, can grow rapidly in response to emerging biological complexity. A model for this expansion is provided through combinatorial innovation by the Theory of the Adjacent Possible (TAP) and its corresponding TAP equation, whose solutions we investigate, confirming the possibility of rapid state-pace growth. While the results of this work remain far from being firmly established, the evidence we provide is many-fold and strong. The implications are far-reaching, and open a variety of lines for future investigation, a new scientific field we term biocosmology. In particular the relationship between the information content in life and the information content in the Universe may need to be rebuilt from scratch.

Read this paper on arXiv…

M. Cortês, S. Kauffman, A. Liddle, et. al.
Thu, 21 Apr 22
40/73

Comments: 35 pages, 1 figure

Biosignature Surveys to Exoplanet Yields and Beyond [EPA]

Posted on by

http://arxiv.org/abs/2005.04005


Upcoming biosignature searches focus on indirect indicators to infer the presence of life on other worlds. Aside from just signaling the presence of life, however, some biosignatures can contain information about the state that a planet’s biosphere has achieved. This additional information can be used to measure what fractions of planets achieve certain key stages, corresponding to the advent of life, photosynthesis, multicellularity, and technological civilization. We forecast the uncertainties of each measurement for upcoming surveys, and outline the key factors that determine these uncertainties. Our approach is probabilistic and relies on large numbers of candidates rather than detailed examination of individual exoplanet spectra. The dependence on survey size, likeliness of the transition, and several measures of degrees of confidence are discussed, including discussion of geological false positives in biosignatures as well as how combining data from different missions can affect the inference. Our analysis should influence policy recommendations for future mission design and strategy to minimize the impact of measurement uncertainties.

Read this paper on arXiv…

M. Sandora and J. Silk
Mon, 11 May 20
51/61

Comments: 17 pages, 9 figures, accepted to MNRAS

How dark can it get at night? Examining how clouds darken the sky via all-sky differential photometry [IMA]

Posted on by

http://arxiv.org/abs/1807.10593


Artificial light at night has affected most of the natural nocturnal landscapes worldwide and the subsequent light pollution has diverse effects on flora, fauna and human well-being. To evaluate the environmental impacts of light pollution, it is crucial to understand both the natural and artificial components of light at night under all weather conditions. The night sky brightness for clear skies is relatively well understood and a reference point for a lower limit is defined. However, no such reference point exists for cloudy skies. While some studies have examined the brightening of the night sky by clouds in urban areas, the published data on the (natural) darkening by clouds is very sparse. Knowledge of reference points for the illumination of natural nocturnal environments however, is essential for experimental design and ecological modeling to assess the impacts of light pollution. Here we use differential all-sky photometry with a commercial digital camera to set an upper limit on the illumination of overcast sites without light pollution. We investigate how clouds alter the sky brightness and color temperature at two rural sites. The spatially resolved data enables us to identify and study the nearly unpolluted parts of the sky, even in a non-ideal scenario. We observe cloud attenuation and red shift not only at zenith, but for most parts of the sky, reducing luminance and illuminance levels for overcast conditions. Our results represent a first step towards finding a reference point for cloudy skies in unlit areas within the context of ecological light pollution.

Read this paper on arXiv…

A. Jechow, F. Hölker and C. Kyba
Mon, 30 Jul 18
20/49

Comments: 16 pages, 6 figures

Mineralogical Characteristics of Harmattan Dust Across Jos North Central and Potiskum North Earthern Cities of Nigeria [CL]

Posted on by

http://arxiv.org/abs/1806.11557


The trace metals and mineralogical composition of harmattan dust carried out on the samples collected at Jos ((9 55’N, 8 55’E)) and Potiskum ((11 43’N, 11 02’E) as revealed by PIXE and AAS machine using clean Petri Dishes and Plastic bowls of 10 cm in diameter aimed on the characteristics of the mineralogical and elemental composition of the harmattan dust carried out in Nigeria. Thirteen trace elements, Na, K, Ca, Mg, Fe, Cd, Zn, Mn, Cu, Si, Al, Ti, and Zr were determined and their concentrations were evaluated in different proportion. Minerals such as Quartz [SiO2], Corundum [Al2O3], Hematite [Fe2O3], Lime [CaO], Periclase [MgO], Rutile [TiO2], Zincite [MnO], Bunsenite [NiO], Cuprite [Cu2O], Zincite [ZnO], Baddeleyite [ZrO2], Litharge [PbO], Monazite [P2O5], Montrodydite [HgO] and Petzite [Au2O3] were also determined in different concentrations. The particle weight of the sample for the residential and commercial areas were calculated to be Jos (18.95g/m2, 19.25g/m2), Potiskum (24.24 g/m2, 2515g/m2) respectively. The results shows that the harmattan dust that blows across the two stations in Nigeria comprise of high elements and more minerals.

Read this paper on arXiv…

O. Falaiye and F. Aweda
Mon, 2 Jul 18
58/70

Comments: 18 pqges, 7 figures

The epistemological status of Astrobiology: a problematic case of integration of scientific disciplines [IMA]

Posted on by

http://arxiv.org/abs/1709.06562


Astrobiology is a scientific discipline that studies life in the Universe. We call it a discipline and not a science because some authors have cast doubts over its epistemological status by calling it ‘a science without an object of study’. As with astrophysics, the scientific nature of astrobiology is related to historical-narrative sciences and nomothetic sciences. This discipline also integrates complex methodological and conceptual problems which originate from the methodological and epistemological differences that exist between physics and biology. This is why it is so important to evidence the different philosophical approaches from which its results are interpreted. After a brief historical introduction, we will consider the problem of life and we will analyse the influence that different philosophical approaches have on astrobiology. Subsequently, we will introduce ontological and epistemological questions that originate from interdisciplinarity, for example, their role in a physicalistic type of reductionism and in teleology.

Read this paper on arXiv…

J. Quemada
Thu, 21 Sep 17
41/50

Comments: 22 pages, bibliography, Spanish. arXiv admin note: text overlap with arXiv:1709.05971

Measuring Light Pollution with Fisheye Lens Imagery from A Moving Boat, A Proof of Concept [CL]

Posted on by

http://arxiv.org/abs/1703.08484


Near all-sky imaging photometry was performed from a boat on the Gulf of Aqaba to measure the night sky brightness in a coastal environment. The boat was not anchored, and therefore drifted and rocked. The camera was mounted on a tripod without any inertia/motion stabilization. A commercial digital single lens reflex (DSLR) camera and fisheye lens were used with ISO setting of 6400, with the exposure time varied between 0.5 s and 5 s. We find that despite movement of the vessel the measurements produce quantitatively comparable results apart from saturation effects. We discuss the potential and limitations of this method for mapping light pollution in marine and freshwater systems. This work represents the proof of concept that all-sky photometry with a commercial DSLR camera is a viable tool to determine light pollution in an ecological context from a moving boat.

Read this paper on arXiv…

A. Jechow, Z. Kollath, A. Lerner, et. al.
Mon, 27 Mar 17
16/40

Comments: 9 pages, 6 figures, accepted at International Journal of Sustainable Lighting

Galactic Distribution of Chirality Sources [EPA]

Posted on by

http://arxiv.org/abs/1612.06720


Biochemical processes are known to utilize only one enantiomer, e.g. amino acids used by terrestrial life are generally the left-handed version. The concepts of chirality, optical activity and chiral enrichment are explored in the context of the origin of life in the universe before Earth. Chirality as a feature of terrestrial life suggests neither a special place for local development of homochirality nor for extra-terrestrial enrichment and delivery. Each seems to have some strengths. Chiral enrichment on asteroids or comets could have been promoted via photon polarization or preferential growth on ice mineral faces or both. Chiral enrichment in situ could have occurred via a variety of processes, including zeolite or sulfide surface templating. Stellar and planetary magnetic fields are discussed as well, and a novel mechanism for geomagnetic reversals is introduced based on analogy with stellar processes. Mineral classes and environments are also explored along with four hypothetical scenarios: asteroid/comet delivery; chemical gardens; geothermal fields; and icy worlds.

Read this paper on arXiv…

D. Helman
Wed, 21 Dec 16
25/67

Comments: Currently submitted as a chapter to an Elsevier volume “Habitability of the Universe Before Earth”, Richard Gordon, Alexei Sharov, eds

A link between solar events and congenital malformations: Is ionizing radiation enough to explain it? [CL]

Posted on by

http://arxiv.org/abs/1503.02576


Cosmic rays are known to cause biological effects directly and through ionizing radiation produced by their secondaries. These effects have been detected in airline crews and other specific cases where members of the population are exposed to above average secondary fluxes. Recent work has found a correlation between solar particle events and congenital malformations. In this work we use the results of computational simulations to approximate the ionizing radiation from such events as well as longer term increases in cosmic ray flux. We find that the amounts of ionizing radiation produced by these events are insufficient to produce congenital malformations under the current paradigm regarding muon ionizing radiation. We believe that further work is needed to determine the correct ionizing radiation contribution of cosmogenic muons. We suggest that more extensive measurements of muon radiation effects may show a larger contribution to ionizing radiation dose than currently assumed.

Read this paper on arXiv…

A. Overholt, A. Melott and D. Atri
Tue, 10 Mar 15
27/77

Comments: Journal of Geophysical Research: Space Physics, in press

Practical Applications of Cosmology to Human Society [CL]

Posted on by

http://arxiv.org/abs/1406.6328


Complex systems throughout Nature display structures and functions that are built and maintained, at least in part, by optimal energies flowing through them–not specific, ideal values, rather ranges in energy rate density below which systems are starved and above which systems are destroyed. Cosmic evolution, as a physical cosmology that notably includes life, is rich in empirical findings about many varied systems that can potentially help assess global problems facing us here on Earth. Despite its grand and ambitious objective to unify theoretical understanding of all known complex systems from big bang to humankind, cosmic evolution does have useful, practical applications from which humanity could benefit. Cosmic evolution’s emphasis on quantitative data analyses might well inform our attitudes toward several serious issues now challenging 21st-century society, including global warming, smart machines, world economics, and cancer research. This paper comprises one physicist’s conjectures about each of these applied topics, suggesting how energy-flow modeling can guide our search for viable solutions to real-world predicaments confronting civilization today.

Read this paper on arXiv…

E. Chaisson
Wed, 25 Jun 14
53/67

Comments: Research paper accepted for publication in Natural Science, v6, no10, pp767-796, 2014; to be published in June 2014 at dx.doi.org/10.4236/ns.2014.610077

The Natural Science Underlying Big History [CL]

Posted on by

http://arxiv.org/abs/1406.2730


Nature’s many varied complex systems (including galaxies, stars, planets, life, and society) are islands of order within the increasingly disordered universe. All organized systems are subject to physical, biological or cultural evolution, which together comprise the grander interdisciplinary subject of cosmic evolution. This is global history greatly extended, big history with a scientific basis, and natural history broadly portrayed across 14 billion years of time. Such evolution writ large has significant potential to unify the natural sciences into a holistic understanding of who we are and whence we came. No new science (beyond frontier, non-equilibrium thermodynamics) is needed to describe cosmic evolution’s major milestones at a deep and empirical level. Quantitative models and experimental tests imply that a remarkable simplicity underlies the emergence and growth of complexity for a wide spectrum of known and diverse systems. In particular, energy rate density is an objective metric suitable to gauge relative degrees of complexity along a hierarchy of widely assorted systems observed throughout the material universe.

Read this paper on arXiv…

E. Chaisson
Thu, 12 Jun 14
49/50

Comments: Review paper accepted for publication in The Scientific World Journal, v2014, 41 pages, article ID 384912; to be published in June 2014 at this http URL

On the habitability of exoplanets orbiting Proxima Centauri [EPA]

Posted on by

http://arxiv.org/abs/1401.3267


We apply a mathematical model for photosynthesis to quantitatively assess the habitability of a hypothetical planet orbiting Proxima Centauri, inside the so called habitability zone. Results suggest significant viability for primary biological productivity, provided living organisms have evolved to reach the ability of using infrared light for photosynthesis.

Read this paper on arXiv…

Wed, 15 Jan 14
66/67

Possibilities of life around Alpha Centauri B [EPA]

Posted on by

http://arxiv.org/abs/1401.2211


We make a preliminary assessment on the habitability of potential rocky exoplanets around Alpha Centauri B. We use several indexes: the Earth Similarity Index, a mathematical model for photosynthesis, and a biological productivity model. Considering the atmospheres of the exoplanets similar to current Earth’s atmosphere, we find consistent predictions of both the Earth Similarity Index and the biological productivity model. The mathematical model for photosynthesis clearly failed because does not consider the temperature explicitly. For the case of Alpha Centauri B, several simulation runs give 11 planets in the habitable zone. Applying to them above mentioned indexes, we select the five exoplanets more prone for photosynthetic life; showing that two of them in principle have better conditions than Earth for this kind of life.

Read this paper on arXiv…

Mon, 13 Jan 14
18/39